Marks obtained are the number of marks you obtain from the total marks given to the paper. While 100 percentile is assigned to the candidate who obtained highest marks in that paper. If a candidate has 97percentile it means he has scored better then the 97 percent of students who appeared for the exam.
Hope you understood.
the marks vs percentile is the number of marks scored is made for the 100 percentile.
for the jee main 2020 you can know your percentile with your marks by clicking the below link:
Hope it helps.
All the best.
Percentile is the criteria which is introduced by NTA for normalization of JEE Scores 2020.
Some conversions are:-
17 to 1 marks - 31 to 9 percentile
27 to 18 marks - 49 to 33 percentile
37 to 28 marks - 62 to 49 percentile
47 to 38 marks - 74 to 64 percentile
57 to 48 marks - 81 to 75 percentile
67 to 58 marks - 87 to 82 percentile
77 to 68 marks - 90 to 87 percentile
87 to 78 marks - 92 to 90 percentile
107 to 88 marks - 95 to 92 percentile
107+ marks - 95+ percentile
You may refer to the source article for more detailed information
If you are interested in knowing colleges for which you are eligible then you should go to the link mentioned below.
Link - JEE Main College Predictor
Hope it helps you.